The Economics of Rush-Hour Traffic Dynamics: Beyond the Bottleneck Model

University Of California-Riverside, Riverside CA

Investigators

Abstract

Traffic congestion is one of the banes of modern life. Surprisingly, however, until recently very little systematic data had been collected on traffic congestion on urban streets (in contrast to freeways), which has hampered the development of well-informed policies for the alleviation of downtown traffic congestion. The recently collected data have generated an important finding: the performance of the urban street system deteriorates sharply under heavily congested conditions -- more sharply than freeways. This has two important policy implications. First, it is important to implement policies that nip traffic jams in the bud. Second, congestion pricing in downtown areas generates even larger social benefits than previously believed. This research effort develops models of rush-hour traffic congestion on urban streets that account for this finding and applies them to analyze the effects of alternative congestion-relief policies. The research will support one Ph.D. student in applied mathematics, and encourage other such students to apply their technical skills to the study of downtown traffic congestion. The bottleneck model has been the workhorse model for the study of rush-hour traffic dynamics for a quarter of a century. While it has generated many insights, it has a serious flaw -- it assumes that traffic flow remains constant under heavily congested conditions. Recent empirical study of the MFD -- macroscopic fundamental diagram -- in downtown areas has shown, to the contrary, that flow falls sharply under heavily congested conditions. Previous work has developed a model of rush-hour traffic dynamics that accommodates the empirical MFD -- the isotropic model of downtown traffic congestion. Unfortunately the model has proven analytically and numerically intractable. The project aims to develop tractable algorithms to solve the model and also make progress in its analytical solution. These tools will lead to more accurate analysis of policies aimed at alleviating downtown traffic congestion, including not only congestion pricing but also parking and congestion management policies.